GPU demo program, run on Raspberry Pi 2

Building on Pi
++++++++++++++
To build the test apps on the pi, first build the libs:
make -C libs/ilclient
make -C libs/vgfont
then by entering each test app directory and run make. E.g.
cd hello_world
make
./hello_world.bin
Running ./rebuild.sh will rebuild the all libs and and apps.
Building on a different PC
++++++++++++++++++++++++++
If you want to build the samples on a different machine (cross-compile) then set:
SDKSTAGE=<path/to/firmware-directory> and CC=<path/to/cross-compiler>
before running make.

To build all the demo program, switch to the folder /opt/vc/src/hello_pi, enter command:
$ ./rebuild.sh